For Rupert Murdoch and Wendy Deng, it was never a case of if but when. But now that the American media magnate and the Chinese-born television executive have tied the knot, speculation is rife that Murdoch's global media empire, News Corp, will never be the same again.

Indeed, no sooner had news of the private wedding ceremony in New York on Friday hit the wires than a Hong Kong astrologer was predicting that Murdoch would father at least two children with Deng.

Given that he already has three children from his previous marriage to Anna Murdoch placed to succeed him in the business, the prediction is said to have brought News Corp executives out in a 'cold sweat'.

Ever since Murdoch began courting Deng a year ago, plucking her from the obscurity of his Star TV franchise in Hong Kong, rumours have been circulating about her future role in the business.

At 32 she is the same age as Murdoch's daughter, Elisabeth, the managing director of his BSkyB satellite channel, and just five years older than Murdoch's oldest son and heir apparent, Lachlan.

Deng is credited with having mellowed Murdoch's famously gruff manners and has even persuaded him to take unscheduled trips to places like Las Vegas without leaving a forwarding number.

But privately many executives are alarmed by her growing influence on the business.

'There's no doubt she's put a spring in the old man's step,' commented one News Corp source. 'But if he keeps going like this, she will wear him out.'

Judging by the secrecy surrounding their nuptials, however, for the moment Murdoch is still very much in control.

The bride wore white, a string ensemble played Mozart and, presumably, at some point in the proceedings the groom said: 'I do.'

But Murdoch ensured that any more intimate details, of the sort his tabloid readers have come to expect from other celebrity weddings, were few and far between.

Indeed, such was the news blackout surrounding the ceremony that some guests seemed unsure whether the wedding had really been going ahead.

'I don't even know if he's getting married, love. We're just coming to a party,' said one guest boarding the private yacht on the Hudson River Murdoch had hired for the twilight ceremony.

'My only comment is no comment,' said Murdoch's longtime spokesman, Howard Rubenstein.

In fact, the only thing stopping Murdoch marrying Deng sooner had been the completion of his divorce from his wife of 32 years, Anna.

Despite rumours that Anna was infuriated by her husband's relationship with a woman 36 years his junior, the couple reached an 'amicable' settlement three weeks ago. Although the details were not disclosed, the agreement left the Murdoch family's 30 per cent stake in News Corp unchanged, apparently guaranteing the position of Anna's three children in the empire.

Now, however, the family is not so sure.

Murdoch's decision to hold the ceremony on board 'The Morning Glory' was no accident - he and Deng courted on a yacht in the Mediterranean last October - and friends say that the romance has rejuvenated the 68-year-old magnate to the extent that he sometimes wears jeans and black T-shirts in public.

Nevertheless, Murdoch was clearly keen not to upstage his son Lachlan, whose marriage to the Australian model Sara O'Hare in March was a far more sumptuous affair.

Whereas Lachlan had a chapel purpose-built in the grounds of the Murdoch family's New South Wales estate and wore a tight-fitting white tuxedo, his father sported an ill-fitting, two-button suit which served to accentuate the age difference with his bride.

To add to the inelegance of the occasion, a number of guests - clearly believing it was a party and not a wedding - turned up in deck shoes. Among the 82 well-wishers were Michael Milken, the former junk bond king, and the Russian entrepreneur Boris Berezovsky.

Wearing a cream-coloured silk-and-lace gown designed by Richard Tyler of Australia, Deng walked up the aisle to the accompaniment of Welsh singing prodigy Charlotte Church.

After the ceremony, conducted by New York Supreme Court Justice Jacqueline Silbermann, the couple kissed for the cameras and then they set sail for an unknown honeymoon destination.

They are now expected to divide their time between New York - where Deng recently persuaded Murdoch to buy a loft in the trendy SoHo district - and Murdoch's mansion in Beverly Hills, California.